Libertarianism isn't about forcing people to be moral. Quite the opposite. It's about not preventing people from doing what they please, with the single caveat that said actions cannot injure another person's body or property or freedom.
People no longer even agree on what those rights are -- how do you propose to define and delimit them?
People don't have rights. Specifically, the First Amendment says you don't have the right to shut anyone up. The Second Amendment says you don't have the right to deny me a gun. The Third says you don't have a right to use my house as a spare barracks. The Fourth Amendment says you don't have the right to search my person or property without a proper warrant. The Fifth says you don't have the right to hold me without indictment (Fifth is invalidated by the PATRIOT Act, apparently),
...etc...
Uh huh. The truth is that libertarianism will work as long as people are already largely self-policing. If people are not, then one gets a spiral toward anarchy instead of an orderly society -- which begets the proliferation of laws to try to limit those who use the letter of the law to get around the (moral) spirit of the law.
A good a non-governmental example is found in mortgage paperwork. A nice libertarian society might expect it to be one sheet of paper -- at most. Why? Well, because a good libertarian would live up to his obligations, of course.
Here in reality, your mortgage closing will have you signing something that's tens of pages long, and just about every sheet and clause has something you must or cannot do -- and just about every one of those was added because somebody tried to get away with something, instead of honoring the spirit of their agreement.